The invention generally relates to external programmers for use with implantable cardiac stimulation devices and to methods for programming implantable cardiac stimulation devices.
A wide range of implantable cardiac stimulation devices are provided for surgical implantation into humans or animals. One common example is the cardiac pacemaker. Another is the implantable cardioverter defibrillator (ICD). Other examples include devices for stimulating or sensing portions of the brain, spinal cord, muscles, bones, nerves, glands or other body organs or tissues. Another example is an implantable drug pump.
Implantable cardiac stimulation devices, particularly pacemakers, are often configured to be used in conjunction with an programmer which allows a physician to program the operation of the device to, for example, control the specific parameters by which the device detects arrhythmia conditions and responds thereto. For instance, the programmer may allow the physician to specify the sensitivity with which the device senses electrical signals within the heart and to further specify the amount of electrical energy to be employed for pacing the heart in circumstances where expected heart signals are not sensed. Additionally, the programmer may be configured to receive and display a wide variety of diagnostic information detected by the device, such as graphs of electrical heart signals sensed by the device and responsive pacing signals. Also, the programmer may operate to analyze the data received from the device to assist the physician in rendering diagnoses as to possible arrhythmias and to assist the physician in programming the device to provide appropriate therapy.
Current state of the art implantable cardiac stimulation devices may have dozens or hundreds of programmable parameters that can be individually programmed using the external programmer. The programmable parameters permit the operation of the cardiac stimulation device to be tailored to the needs of the particular patient to provide optimal therapy while minimizing the risk of any unnecessary therapy. Unfortunately, it is often difficult to predict what the resultant operation will be for any given patient with any selected set of parameter settings. Hence, a potentially viable set of parameters is chosen by the physician, the implantable cardiac stimulation device is programmed using the selected set of parameters, and then the patient is sent home. Weeks or months later the patient must return to the physician""s office for a follow-up appointment so that they physician may evaluate the results of the selected parameters. Typically, the follow-up evaluation consists of the physician making judgments based upon observing several characteristics of the patient and of the implanted cardiac stimulation device. If the device is a pacemaker, the physician typically reviews intracardiac electrogram (IEGM) data recorded by the cardiac stimulation device and also reviews information pertaining to the present operating status of the device via telemetric interrogation of diagnostic data stored within the device. The diagnostic data may, for example, specify the operation of the device over a prior recording period, such as over the last few weeks or months. Specific types of diagnostic information that may be provided includes information identifying the percentage of paced versus sensed beats, heart rate histograms, sensor rate histograms, etc. Additional diagnostic information specifies the battery voltage, lead impedance, etc. of the device. The physician collates the information and makes adjustments to the programming of the device. Again, the patient is sent home for several more weeks or months until another follow-up visit. This cycle may be repeated numerous times before optimal device settings are determined by the physician.
As can be appreciated, it would be highly desirable to limit the need for patients to return to the physician for follow-up sessions, to thereby reduce the cost and inconvenience to the patient and to permit the physician to devote a greater amount of time to the more urgent needs of other patients. One solution that has been proposed is to provide the patient with a telemetry device for receiving programming commands via telephone from a programmer maintained by the physician and for relaying programming commands to the implantable cardiac stimulation device within the patient via remote telemetry. In this manner, the physician can reprogram the implantable cardiac stimulation device without requiring the patient to return to the physician""s office.
One concern with the proposed system is that, if the remote device is operated only under the control of the patient, incomplete or improper programming of the implanted device may occur. In this regard, patients with implanted cardiac stimulation devices are often elderly and, in at least some cases, are not able to reliably position a hand-held telemetry unit of the remote device in proximity to the implanted device throughout an entire reprogramming session. As a result, only a portion of reprogramming commands transmitted from a central programmer may be received by the implanted device, possibly resulting in improper programming of the device. Depending upon the parameters being reprogrammed, the improper reprogramming may result in significant changes in the operation of the implanted device, perhaps resulting in a loss of consciousness of the patient. As can be appreciated, if the patient is at home and unattended by a nurse or physician, it may be necessary to send an ambulance to the home of the patient to revive the patient. However, if the remote programming device is installed within a nursing clinic, hospital emergency room, or the like, where the remote programming unit may be operated under the control of a nurse or other medical professional, the aforementioned concerns are not an issue. Accordingly, it would be highly desirable to provide a remote programming system which controls the type of reprogramming permitted using a remote programming device based upon the degree of supervision of the patient and it is to that end that aspects of the invention are directed.
Another concern with the proposed remote programming system is that the cost of the remote unit may be quite high, thus discouraging physicians from providing the remote programmers to their patients or discouraging insurance companies from paying for the remote programmers. For example, one specific proposed remote programming system for use by an patient (discussed in U.S. Pat. No. 5,752,976) includes a wireless or cellular telephone and a geosynchronous positioning system (GPS) transceiver. The wireless or cellular telephone permits the patient to converse with the physician and also to receive and transmit programming commands, diagnostic information and the like. The GPS system permits the location of the patient to be determined, particularly if the patient is unable to respond to telephonic requests by the physician. Although the system permits remote reprogramming of the implantable cardiac stimulation device, the inclusion of a wireless telephone and GPS system may render the remote system quite expensive, and thereby only appropriate for certain high risk patients. Accordingly, it also would be desirable to provide an remote programming system which is relatively inexpensive to thereby permit most or all patients to receive the benefits of remote programming and it is to this end that others aspects of the invention are directed.
In accordance with the invention, a system is provided for remote programming of an implantable cardiac stimulation device implanted within a patient. The system includes a central programmer device operative to generate and transmit programming signals for use in programming a stimulation device implanted within a patient. The programming signals are generated, in part, based upon a degree of direct medical supervision of the patient during programming of the device. A remote programmer device is provided for use in proximity to the patient a remote programmer device. The remote programmer device is operative to receive and relay the programming signals transmitted by the central programmer device to the stimulation device of the patient to program the stimulation device with the programming signals.
In an exemplary embodiment, the implantable cardiac stimulation device is a pacemaker or ICD. The degree of supervision is either supervised or unsupervised. If unsupervised, remote programming of only non-life-threatening functions is permitted, such as programming of diagnostic functions, sleep mode functions, and the like. Programming of other functions, such as sensitivity parameters, pacing mode parameters, is not permitted or, if permitted, is restricted to particular ranges of programming values. If the patient is supervised, however, a full range of programming parameters and values is permitted. Depending upon the implementation, the indication of the degree of supervision may be manually entered into the central programmer by the physician or automatically determined by querying the remote device. Additional levels of supervision maybe accommodated as well, such as physician-supervised, nurse-supervised or unsupervised. By controlling the generation of programming signals based on the degree of supervision of the patient, the risk of improper or incomplete programming of critical parameters of the implanted device is substantially avoided.
Also, in the exemplary embodiment, the remote programmer device includes only those components necessary to relay programming signals and diagnostic information between the central programming device and the implantable cardiac stimulation device such that the costs associated with the remote programmer device are minimal.
In another exemplary embodiment, the remote programmer additionally includes a Holter monitor for detecting and recording surface electrocardiogram (ECG) signals. The remote device additionally includes a modular memory unit for storing the recorded signals. The modular memory unit also stores control software for controlling the operations of the remote programmer permitting the remote programmer to be easily upgraded to operate in conjunction new or modified implanted devices.